triglycerides: composed of & percentage in food & body

phospholipid: composed of, where found & main function

- Chemically similar to a triglyceride, 1 fatty acid is replaced by a compound containing phosphorus and nitrogen groups
- Lecithin- main phospholipid in foods, such as egg
yolks, liver, wheat germ, peanut butter, and soy
- Phospholipids form a bilayer in water
• The bulk of all cell's plasma or cell membrane is a phospholipid bilayer with embedded proteins

Phospholipids: emulsifiers

- Phospholipids act as emulsifiers, because they have hydrophobic and hydrophilic regions. need for digestion b/c enzymes can get to fat when emulsified
- Hydrophobic region
• Attracts lipids and avoids water
- Hydrophilic region
• Attracts water and avoids lipids

cholesterol: description, where found, functions & uses

1. Cholesterol is a sterol, a compound that is more complex than most other lipids.
• is found in all animal cell membranes
• is nonessential
• forms plaques that cause atherosclerosis
2. Cholesterol serves as the raw material for
•Bile
• vitamin D
• Steroid ￼ hormones including the sex hormones

lipoproteins

-water-soluble structures that transport lipids thru the bloodstream.
-The just-eaten fat travels in the bloodstream as CHYLOMICRONS.
- Body tissues can extract whatever fat they need from chylomicrons.
- The remnants are then picked up by the liver, which dismantles them and reuses their parts.

Very-low-density lipoproteins (VLDL)

- carry triglycerides and other lipids made in the liver to the body cells for their use.
• VLDL primarily carries triglycerides. if in the liver will increase cholesterol
- High levels may contribute to atherosclerosis

Low-density lipoproteins (LDL)

- transport cholesterol and other lipids to the tissues. LDL are made from VLDL after they have donated many of their triglycerides to body cells.
- LDL commonly called "bad" cholesterol
• Conveys cholesterol TO the tissues/cells
• May become oxidized (sticky) LDL and contribute to atherosclerotic plaque
- larger, lighter, and richer in cholesterol. Deliver cholesterol and triglycerides from the liver to the tissues.
- LDL - Less healthy

High-density lipoproteins (HDL)

-are critical in the process of carrying cholesterol for disposal.
HDL commonly called "good￼ " cholesterol
• Transports cholesterol from tissues and to the liver (to make bile) where it can be eliminated. away from plaque build up
- smaller, denser, and packaged with more protein. HDL scavenge excess cholesterol and phospholipids from the tissues for disposal.
- HDL = Healthy

recycling bile salts

Enterohepatic Circulation
- After bile salts are used to aid lipid digestion, the salts are absorbed in the ileum and return to liver for the production of new bile.
- Soluble fibers and plant sterols/stanols interfere with bile and cholesterol absorption. (good thing not returned to liver, so liver must use cholesterol to make new bile salts)
Note: Some synthetic margarine spreads contain plant sterols or stanols.

How Can I Use My Stored Fat For Energy?

- When low on fuel, the body draws on its stored fat for energy.
- Fat cells respond to the call for energy by dismantling stored fat molecules and releasing fat components into the bloodstream.
- Upon receiving these components, cells break them down further into fragments. Each fragment is combined with a fragment derived from glucose, and the energy-releasing process continues, liberating energy, carbon dioxide, and water.
- Without glucose (carbs), fat is incompletely broken down to ketones

Lipids acceptable range & US dietary guidelines

Lipids & Health: Cardiovascular disease (CVD)

CVD: diseases of the heart and blood vessels
Most common forms of CVD are:
• Heart disease ("coronary artery disease")
• Stroke
1 in 3 adult Americans have some form of CVD. - -
-Responsible for ~ ￼36 % of deaths in the U.S.

artherosclerosis: what is it & what can result

— disease in which lipid- containing plaques build up inside arteries
Plaque forms in an artery when something irritates the lining of the artery wall.
• Plaque narrows arteries, interfering with circulation. • Plaque may also result in the formation of a fixed clot— a thrombus.

embolus formation

A thrombus (blood clot) that breaks away and travels through the blood is an embolus.
- If an embolus lodges in the heart, it can cause a heart attack (myocardial infarction).
- If an embolus lodges in the brain and deprives brain cells of oxygen and nutrients, a stroke results.

desirable levels of lipoproteins

High-sensitivity C-reactive protein (hs-CRP)

•Protein produced primarily by liver in response to infection and inflammation
•Marker for CVD and hypertension
- marker for inflammation (including arteries)
Note: A "marker" is an early physiological warning sign that can be measured.

dietary recommendations: Limits on fats

Limit:
- Saturated fats to <7% of total kcal
- Trans fats to <1% of total kcal
- Total fat to 35% or less of total kcal
-Choose unsaturated fats (esp. monounsaturated) to replace saturated and trans fats.

how body process alcohol

• Alcohol requires no digestion.
- Rapidly absorbed in the mouth, esophagus, stomach, and small intestine
•Detoxification: begins in stomach where alcohol dehydrogenase metabolizes ~20% of alcohol consumed.
- Most alcohol is absorbed in small intestine.
- Travels to the liver where it is metabolized.

￼￼Main pathway for alcohol metabolism (2)

2nd pathway for alcohol metabolism

1. At high doses, the liver's ability to metabolize alcohol using the dehydrogenase pathway is overwhelmed.
- Under these conditions, the microsomal ethanol oxidizing system (MEOS) is used.
- MEOS wastes energy as the heat produced dissipates into the environment.

factors that influence alcohol metabolism (2)

1. Gender
- Men have more gastric alcohol dehydrogenase
- men have larger livers that can metabolize more alcohol at a time
2. Prior drinking history
- Regular drinkers develop tolerance.
- Level of alcohol-detoxifying liver enzymes increase.
- As tolerance increases, alcohol dependence (alcoholism) is likely to occur.

alcohol abuse & dependence

• People who abuse￼ alcohol drink to the extent that it harms their mental and physical health as well as their relationships.
• About 17% of men and 8% of women become dependent on alcohol at some point in their lives.

alcohol dependence (3)

alcohol and health

Effects vary from person to person due to:
- Differences in overall health/brain shrinks
- Drinking habits
- Genetic backgrounds
Alcohol affects every cell in the body, and excesses can do damage to every organ system

alcohol & GI tract (3)

alcohol & the brain (3)

-Effects on the CNS appear within a few minutes after consumption.
-Acts as a depressant, slowing transmission of messages between nerve cells.
-Effects on the brain vary and depend on blood alcohol concentration (BAC)

effect of alcohol & nutritional status

alcohol & body water

￼• Alcohol is not a "thirst quencher."
• It is a diuretic￼ that suppresses the production of antidiuretic hormone (ADH).
- As a result, kidneys excrete more urine, which is mostly water, and certain minerals and vitamins.
- more water than normal leaves the body

alcohol & physical performance

• American College of Sports Medicine recommendations:
- Athletes should learn about alcohol's effects on health.
- Avoid excessive alcohol during the 48 hrs before an event.
- After exercise, avoid alcohol until body is rehydrated